111HIGHLIGHTS 2020

Selective CO2 electroreduction to ethylene and multicarbon alcohols via electrolyte- driven nanostructuring, D. Gao (a), I. Sinev (a,b), F. Scholten (a,b), R.M. Aran-Ais (a), N.J. Divins (a,b), K. Kvashnina (c,d), J. Timoshenko (a) and

B. Roldan Cuenya (a), Angew. Chem. Int. Ed. 58, 17047-17053 (2019); https://doi. org/10.1002/anie.201910155. (a) Department of Interface Science, Fritz Haber Institute of the Max Planck Society, Berlin (Germany)

(b) Department of Physics, Ruhr-University Bochum (Germany) (c) ESRF (d) Institute of Resource Ecology, Helmholtz Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany)

[1] R.M. Aran-Ais et al., Nat. Energy 5, 317-325 (2020). [2] D. Gao et al., Nat. Catal. 2, 198-210 (2019). [3] P. Grosse et al., Angew. Chem. Int. Ed. 57, 6192-6197 (2018). [4] D. Gao et al., ACS Nano 11, 4825-4831 (2017). [5] D. Gao et al., ACS Catal. 7, 5112-5120 (2017). [6] D. Gao et al., ACS Catal. 8, 10012-10020 (2018).

LIQUID BISMUTH AND ENHANCED SYNTHESIS OF LIGHT OLEFINS FROM SYNGAS OVER IRON CATALYSTS

Remarkable mobility and reduction-oxidation cycles of the bismuth promoter in the working iron Fischer-Tropsch catalysts were uncovered using a combination of in-situ XANES, in-situ STEM and NAP-XPS. These phenomena resulted in a several-fold increase in the reaction rate and in a major increase in the light olefin selectivity.

PRINCIPAL PUBLICATION AND AUTHORS

REFERENCES

It should be noted that a synergistic combination of complementary characterisation techniques is of key importance to obtain in-depth fundamental insight into structure/ chemical state/reactivity correlations. In the present study, detailed spectroscopic and microscopic analysis was key to extract correlations between the high C2+ selectivity of nanostructured Cu catalysts and their induced highly roughened surface morphology, the presence of subsurface oxygen and Cu+ species as well as electronic modifications brought about by the adsorbed halides. This work provides new insight into the parameters that can be tuned in

order to rationally design C2+-selective CO2RR catalysts.

The energetic transition and growing demand for platform molecules produced from renewable feedstocks require the design of novel catalysts and a better understanding of the evolution of the catalytically active phases at the nanoscale level. Iron catalysts are the catalysts of choice for light olefins synthesis from syngas, which can be generated by gasification of biomass and plastic waste as well as fossil carbon resources. Recently, it was observed that doping of iron

catalysts with soldering metals, which were liquid at the reaction temperature, could significantly enhance their performance in Fischer-Tropsch synthesis [1]. Doping of iron catalysts with bismuth resulted in a 10-fold increase in the yield and in a 60% increase in the selectivity to light olefins. Moreover, over the optimised catalysts, Fischer-Tropsch synthesis occurred even under atmospheric pressure with high conversion and enhanced selectivity to light olefins.

Fig. 93: Operando HERFD-XANES spectra of (a) Cu_I and (b) Cu_Br measured in the as-

prepared state and under CO2RR conditions. Linear combination analysis (LCA) of

operando HERFD-XANES spectra of Cu_I measured (c) in the as-prepared state and

(d) under CO2RR conditions.